Cryogenic heat exchanger



April 6, 1965 THEOCLITUS 3,

, CRYOGENIC HEAT EXCHANGER Filed April 4, 1962 2 Sheets-Sheet 1 INV EN TOR. reyory Head/fur AGENT A ril 6, 1965 cs. THEOCLITUS 3,175,758

CRYOGENIC HEAT EXCHANGER Filed April 4, 1962 2 Sheets-Sheet 2 INVENTOR. 6 7/; /'z BY reyo/y eoc/ a:

flGE/VT CRYOGENIC MAT EXCHANGER Gregory Theoclitus, Wellsville, N.Y., assignor, by mesne assignments, to Combustion Engineering, Inc, a stock corporation of Delaware Filed Apr. 4, 1962, Ser. No. 185,016 6 Claims. (Cl. 165-5) The present invention relates to regenerative heat exchange apparatus, and particularly to apparatus of the rotary type that includes a rotor having a mass of heat absorbent element that is carried alternately between a cooling fluid and a fluid to be cooled in order that the temperature of the fluid to be cooled may be reduced as desired.

Most heat exchange equipment is designed to utilize the waste heat that is contained in hot exhaust gases to .preheater air for combustion or other process gases as may be desired, and as such it is especially adapted for use at the high temperatures associated therewith. Recent developments in the field of cryogenics has however defined a need for heat exchange equipment in the cold and ultra cold temperature ranges that are associated with various processes that utilize liquid oxygen, nitrogen or hydrogen.

The apparatus may be classified generally as being of the type disclosed in my co-pending application Serial No. 97,519 filed on March 22, 1961, now Patent No. 3,138,198 issued June 23, 1964 in which fluids flowing through a rotary regenerative heat exchange apparatus are directed in a direction that opposes movement of the heat absorbent element contained therein. Such apparatus is highly eflicient from a heat transfer standpoint, and if made in accordance with the present invention provides unique advantages that permit complete isolation of the various fluids traversing the heat exchanger. Moreover, the arrangement provides for a periodic purging of the element compartments to remove various constituent elements of the several fluids as they condense out during a change of temperature.

It is therefore the principal object of this invention to provide a heat exchanger having maximum utility in the ultra cold temperature zones that are associated with the use of liquified nitrogen, hydrogen or other gas. In the process of liquifying air for example, its various constituent elements condense out and solidify before the temperature of the air reaches its absolute minimum. Thus moisture from the air may condense and then freeze to be followed by -a lower temperature by the condensation and solidification of carbon dioxide. In a solid state, each of these constituents of air would plug the openings of a heat exchange element if they were not removed from the system. The particular details of this invention are therefore directed to an arrangement for a rotary regenerative heat exchanger of the counterflow type that permits a continuous purging action in a plurality of temperature zones whereby the apparatus may be adapted for continuous low temperature application.

This and other objects of my invention will become more apparent when viewed in conjunction with the following detailed description and drawings in which:

' FIGURE 1 is a perspective View of arotary regenerative heat exchanger, partially broken away to show the construction of the present invention. FIGURE 2 is an outstretched View of the apparatu of FIGURE 1 showing the flow pattern of the various passageways therethrough.

FIGURE 3 is an enlarged view of a portion of FIG- URE 2 showing the size and space relationship of various ducts, compartments and passagewaysof the apparatus. 1 r In the drawing the rotor comprises essentially a cylin- United States Patent iijlflfi 'a Patented Apr. 6, 1965 drical rotor shell 12 that is joined to a central rotor post 14 by a series of imperforate radial partitions 16 to provide a multiplicity of sectorial compartments 18 therebetween. An annular partition 22 intermediate the rotor post 14 and the rotor shell 12 divides each sectorial compartment into radially spaced inner and outer sections. Each outer section is provided with radial plates 24 at axially spaced ends thereof that cooperate with arcuate portions of the adjoining rotor shell 12 and annular partition 22 to provide a frame-like enclosure 25 having oppositely facing open ends 27. Each frame-like enclosure is adapted to carry a mass of perforate heat absorbent material 32 while the open ends of the frame-like enclosures contront but are spaced from the adjacent radial partitions 16 to permit fluid flow to and from the mass of heat absorbent material 32 that is carried in each enclosure. 7

The rotor is turned about its axis continuously by a driving means and reduction gear arrangement 35 at a speed compatible with the process or heat exchange operation being carried out within the heat exchange apparatus.

A cylindrical housing 36 concentrically surrounds the rotor and isprovided at opposite ends thereof with end plates 38 and 40 that are apertured at a multiplicity of designated locations to receive various ducts that direct fluid to and through the rotor. Thus duct 42 is the inlet and duct 44 is the outlet for a first fluid being cooled, while a second or cooling fluid enters at 46 and exhausts at 43. A purging fluid is directed through the rotor on both sides of the cooling fluid to purge all traces of the cooling fluid from the rotor. Thus an inert purging fluid directed through inlet and exhaust ducts 5.3 and 54 on one side and through ducts 57 and 58 on the other side of the cooling fluid eiiectively precludes mixing of the cooling fluid With the fluid to be cooled that enters duct 42 and is exhausted at 44-.

The end plates 38 and 40 are provided with imperferat-e portions 52 that lie between inlet and outlet ducts for the several fluids in order that these ducts may not at any time be directly connected one with another. These imperforate portions 52 of the end plate are accordingly formed to extend arcuately a distance somewhat greater than the width of a single rotor compartment to insure there always being at least one radial partition 16 therebetween.

To permit a continuous flow of fluid serially through adjacent compartments of the rotor that lie between their respective inlet and outlet ducts, by-pass ducts 55 are secured to end plate 40 and by-pass ducts 60 are secured to end plate 38 to enclose aperturesthat extend circumferentially a distance somewhat less than does an arcuate plate 24. Thus fluid flowing between inlet and outlet ducts for the respective fluids cannot by-pass an entire enclosure of heat absorbent element 32 but will by-pass only the imperforate partition ,16 that lies between adjacent compartments. Bypass ducts 55 and 6d at opposite ends of the housing are oil-set circumferentially a distance equal approximately to one-halfthe circumferential extent of each by-pass opening in order taht fluid flowing serially between adjacent enclosures will flow continuously atone end or the other, even when a partition 16 moves into align ment with any of the walls 59 that separate adjacent by- :pass ducts. For a similar reason the inlet and outlet ducts for the cooling fluid, the fluid to be cooled and the purging fluid have a width greater than that of plate 24. Thus when a plateZdmoves into registry with any of thee ducts it cannot terminate fluid flow,. but.

fluid will continue to flow on a momentarily restricted basis until the plate 24- has moved past the opening In addition to the by-pass ducts 55 and (ill at opposite ends of the housing, a first Zone by-pass duct 62 is formed to isolate a section of the rotor and permit the independent passage of a purging fluid through a number of element compartments that lie bet men an inlet 64 and an outlet as for the purging fluid. A second zone by-pass duct 6% circumferentially spaced from by-pass duct 62 permits a second purging fluid to traverse a limited section of the rotor lying between ducts '72 and '74 at a temperature range that differs substantially from that embraced by by-pass 62.

inasmuch as by-pass ducts 62 and d8 embrace Zones of decreasing temperature, the purging fluid entering duct 64 and exhausting through duct 66 as embraced by the first Zone by-pass serves to purge condensed moisture from the system While the purging fluid for the second zone by-pass removes low temperature condensation from a much colder zone.

To illustraternore fully the operation of the apparatus with respect to specific fluids, let us assume that liquid hydrogen at approximately 260 C. enters inlet 46 and passes to outlet 48 during which passage it traverses the intervening frames of element 32 that are continuously being moved in the opposite direction as indicated in FIG- URE 2. Residual hydrogen remaining in the element 32 and its surrounding compartment is removed therefrom by a purging fluid such as nitrogen which enters the sysduct 48 and the inlet 42 for the air to be cooled.

Air to be cooled enters inlet duct 42 and flows through two adjacent frames of heat exchange elements 32 before it is exhausted through duct 76 to the first zone hy-pass duct 62. Duct 62 skips a plurality of compartments to enter therotor again through an inlet duct 7%. Here the air is again directed through several adjacent rotor compartments in contact with the cold heat absorbent element that is moving away from its contact with the liquid hydrogen entering the system through inlet 46. Moisture in the air condenses on the surface of heat absorbent element and is carriedon to a purge Zone where a purging fluid directed through inlet 64 passes through the frames of element and serves as a carrier to deliver the moisture to the outlet duct as. Relatively dry air then leaves the housing via outlet duct 32 and again skips four compartments to enter duct 86 and again traverse the now very cold elements and be discharged through outlet duct 44. During this last pass through the element compartments of the rotor, carbon dioxide from the air condenses on the surface of the elements and is carried on to an adjoining purging section where a final purging action by a purging fluid entering through inlet duct 72 sweeps away the condensed carbon dioxide and exhausts it from the system via outlet duct 74.

It is to be understood that mechanical sealing means of conventional form may be used as needed to separate the relatively movable parts of the apparatus. Such means however comprise no part of this invention and have been omittedfor the sake of pictorial clarity. It is evident'that various other changes may be made without departing from the spirit of the invention, and it is intended that all matter contained in the above description or shown in the acompanying drawings shall be interpreted as illustrative and not in a limiting sense.

therebetween, radial plate means at axially spaced ends of each compartment combining with adjacent rotor structure to provide an open ended frame having its open ends laterally spaced from and confronting the radial partitions, a mass of perforate heat exchange material carried by each open ended frame, a housing surrounding said rotor, circumferentially spaced inlet and outlet ducts in said housing for a firstfiuid, inlet and outlet ducts in said housing for a second fiuid, by-pass ducts in the housing between inlet and outlet ducts for each fluid arranged to permit each fluid to by-pass the radial partitions and flow serially between frames of heat exchange material carried by the rotor, said by-pass ducts intermediate the inlet and outlet ducts for the first fluid including duct means that by-pass a plurality of consecutive compartments, and other inlet and outlet ducts in said housing having ingress and egress to the consecutive bypass compartments to permit a purging fluid to traverse the open ended frames passing thereby and remove residual matter therefrom.

2. Rotary regenerative heat exchange apparatus havmotor in spaced relation thereto having circumferentially spaced inlet and outlet ducts for a first fluid circumferentially spaced inlet and outlet ducts in said housing for a second fluid, by-pass ducts in the housing between inlet and outlet ducts for each fluid arranged to permit the fluids to by-pass the radial partitions and flow serially between consecutive frames of heat exchange material carried by the rotor, said by-pass ducts intermediate the inlet and outlet ducts for the first fluid including duct means that by-pass a plurality of consecutive compart ments therebetween, other inlet and outlet ducts in said housing having ingress and egress to the consecutive compartments lay-passed by the first fluid and to the compartments embracing inlet and outlet ducts for the first and second fluids whereby the flow of purging fluid theret'hrough displaces residual matter contained therein.

3. Rotary regenerative heat exchange apparatus having arotor comprising a central rotor post, a cylindrical rotor shell concentrically. spaced from the rotor post, radial partitions extending from the rotor post to the rotor shell to provide a series of rotor compartments therebetween, plate means extending radially at axially spaced ends of each compartment combining with other rotor structure to provide an open ended frame having its open ends spaced from and confronting the radial partitions, a mass of perforate heat exchange material carried by each open ended frame, a housing surrounding the rotor in closely spaced relation thereto, circumferentially spaced inlet and outlet ducts at one end of the housing for a first fluid, circumferentially spaced inlet and outlet ducts at the same end of said housing for a second fluid,

by-pass ducts in said housing between inlet and outlet ducts for. each fluid arranged to permit the fluids to bypass the radial partitions and flow serially through adja cent frames of-heat exchange material that lie between their respective inlet and outlet ducts, said by-pass ducts ing a rotor that comprises a central rotor post, a cylin drical rotor shell concentrically spaced from the'rotor post, radial partitions that extend from the rotor post to the rotor shell to provide a series of rotor compartments therebetween, plate means extending radially at axially spaced ends of said compartments combining with other rotor structure to provide a series of open ended frames having their open ends spaced from and confronting the radial partitions, a mass of perforate heat exchange material carried by each frame, a housing surrounding the rotor in closely spaced relation thereto, means for rotating the rotor about its axis, circtuniferentially spaced inlet and outlet ducts at one end of said housing for a first fluid, circumferentially spaced inlet and outlet ducts at the same end of the housing for a second fluid, by-pass ducts in said housing between inlet and outlet ducts for each fluid arranged to permit the fluids to by-pass the radial partitions and flow serially through adjacent frames of heat exchange material lying between inlet and outlet ducts for the respective fluids as the rotor is rotated about its axis, said byapass ducts including a pair of ducts that each by-pass a multiplicity of adjacent compartments, and independent inlet and outlet ducts to said lay-passed compartments adapted to direct the flow of an independent purging fluid therethrough.

5. Rotary regenerative heat exchange apparatus having a rotor that comprises a central rotor post, a cylindrical rotor shell concentrically spaced from the central rotor post, radial partitions extending from the rotor post to the rotor shell to provide a series of sectorial compartments therebetween, arcuate plate means intermediate the rotor post and rotor shell in adjacent sectorial compartments arranged to provide a composite annular wall intermediate the rotor post and rotor shell that divides the sectorial compartments into inner and outer sections, plate means extending radially at axially spaced ends of the outer sections of each compartment abutting said arcuate plate means and the arcuate surface of said rotor shell to form therewith a series of open -housing for a first fluid, circumferentially spaced inlet and outlet ducts at the same end of said housing for a second fluid, by-pass ducts in said housing between inlet and outlet ducts for each of said fluids arranged to permit the fluids to bypass the radial partitions as the rotor is rotated about its axis and flow serially through adjacent frames of heat exchange material that lie between inlet and outlet ducts for the respective fluids, said by-pass ducts including duct means that by-pass a multiplicity of adjacent compartments, and independent inlet and outlet ducts connected to the compartments by-passed by said first fluid adapted to direct a purging fluid therethrough.

6. Rotary regenerative heat exchange apparatus as defined in claim 5 having means directing a purging fluid through the heat absorbent material in advance of and following passage therethrough of said second fluid.

References Cited by the Examiner UNITED STATES PATENTS 2,468,826 5/49 Karlsson et al. -8 XR 2,540,733 2/51 Holm 165-7 FOREIGN PATENTS 5 45,523 3/32 Germany. 853,903 11/60 Great Britain.

CHARLES SU'PALO, Primary Examiner.

FREDERICK L. MATTESON, In, Examiner. 

1. ROTARY REGENERATIVE HEAT EXCHANGE APPARTUS HAVING A CYLINDRICAL ROTOR INCLUDING A CENTRAL ROTOR POST, A ROTOR SHELL CONCENTRICALLY SPACED FROM THE ROTOR POST, RADIAL PARTITIONS EXTENDING FROM THE ROTOR POST TO THE ROTOR SHELL TO PROVIDE A SERIES OF ROTOR COMPARTMENTS THEREBETWEEN, RADIAL PLATE MEANS AT AXIALLY SPACED ENDS OF EACH COMPARTMENT COMBINING WITH ADJACENT ROTOR STRUCTURE TO PROVIDE AN OPEN ENDED FRAME HAVING ITS OPEN ENDS LATERALLY SPACED FROM AND CONFRONTING THE RADIAL PARTITIONS, A MASS OF PERFORATE HEAT EXCHANGE MATERIAL CARRIED BY EACH OPEN ENDED FRAME, A HOUSING SURROUNDING SAID ROTOR, CIRCUMFERENTIALLY SPACED INLET AND OUTLET DUCTS IN SAID HOUSING AOR A FIRST FLUID, INLET AND OUTLET DUCTS IN SAID HOUSING FOR A SECOND FLUID, BY-PASS DUCTS IN THE HOUSING BETWEEN INLET AND OUTLET DUCTS FOR EACH FLUID ARRANGED TO PERMIT EACH FLUID TO BY-PASS THE RADIAL PARTITIONS AND FLOW SERIALLY BETWEEN FRAME OF HEAT EXCHANGE MATERIAL CARRIED BY THE ROTOR, SAID BY-PASS DUCTS INTERMEDIATE THE INLET AND OUTLET DUCTS FOR THE FIRST FLUID INCLUDING DUCT MEANS THAT BY-PASS A PLURALITY OF CONSECUTIVE COMPARTMENTS, AND OTHER INLET AND OUTLET DUCTS IN SAID HOUSING HAVING INGRESS AND EGRESS TO THE CONSECUTIVE BYPASS COMPARTMENTS TO PERMIT A PURGING FLUID TO TRAVERSE THE OPEN ENDED FRAME PASSING THEREBY AND REMOVE RESIDUAL MATTER THEREFROM. 